The invention relates to a colour photographic silver halide material comprising a novel cyan coupler and a chloride-rich silver halide emulsion which is particularly suitable as copying material.
Colour photographic copying materials are, in particular, materials for images to be viewed by reflection or displays which generally have a positive image. They are therefore not recording materials such as colour photographic films.
Colour photographic copying materials conventionally contain at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler.
Photographic copying material, such as colour photographic paper, is produced in a few production sites from where it is sent all over the world and is finally processed by exposure and processing into colour photographic prints. Between production and processing the material is stored for different lengths of time and under a wide variety of conditions. Cold storage and cold transportation prescribed by the producer not only result in high costs but are also frequently not adhered to, This is detrimental to the quality of the colour prints and leads to complaints.
There is therefore a need to produce colour photographic materials, in particular colour photographic paper, which does not require cold storage and also does not exhibit sensitometric changes, in particular in the red-sensitive layers, over a prolonged period of storage at 20 to 50xc2x0 C.
It is known from DE 19 634 385 that, by combining a certain pentamethine cyanin red sensitiser with at least two specific stabilisers, the stability in storage, in particular the gradation stability, of unprocessed colour copying material, may be improved. However, this measure leads to unsatisfactory latent image stability.
However, in copying material according to the prior art, the latent image stability is still unsatisfactory.
The object of the invention was to overcome the disadvantage described above and to thus obtain materials which have very good latent image stability as well as very good stability in storage. Surprisingly, this has been achieved with the cyan coupler defined hereinafter, chloride-rich silver halide emulsions and certain stabilisers.
The invention therefore relates to a colour photographic silver halide material comprising a substrate, at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, characterised in that the silver halide crystals of the red-sensitive layer have a chloride content of at least 95 mol %, the cyan coupler corresponding to the formula 
wherein
R1 represents a hydrogen atom or an alkyl group,
R2 represents an alkyl, aryl or hetaryl group
R3 represents an alkyl or aryl group,
R4 represents an alkyl, alkenyl, alkoxy, aryloxy, acyloxy, acylamino, sulphonyloxy, sulphamoylamino, sulphonamido, ureido, hydroxycarbonyl, hydroxycarbonylamino, carbamoyl, alkylthio, arylthio, alkylamino or arylamino group or a hydrogen atom and
Z represents a hydrogen atom or a group which may be split off under the conditions of chromogenic development and
the red-sensitive layer contains at least one compound of formula 
wherein
R5 represents H, CH3 or OCH3,
R6 represents H, OH, CH3, OCH3, NHCOxe2x80x94R7, COOR7, SO2NH2, NHCONH2 or NHCONHxe2x80x94CH3 and
R7 represents C1 to C4 alkyl
The compound (II) is preferably added in an amount of 50 to 5,000 mg per kg Ag and particularly preferably in an amount of 200 to 2,000 mg per kg Ag of the red-sensitive layer.
The cyan coupler particularly preferably corresponds to the formula 
wherein
R8 represents a hydrogen atom or an alkyl group
R9 represents OR10 or NR11R12,
R10 represents an unsubstituted or substituted alkyl group with 1 to 6 carbon atoms,
R11 represents an unsubstituted or substituted alkyl group with 1 to 6 carbon atoms,
R12 represents a hydrogen atom or an unsubstituted or substituted alkyl group with 1 to 6 carbon atoms,
R13 represents an unsubstituted or substituted alkyl group and
Z represents a hydrogen atom or a group which may be split off under the conditions of chromogenic development,
wherein the total number of carbon atoms of the alkyl groups R10 to R13 in a coupler molecule is 8 to 18.
The alkyl groups can be straight chain, branched or cyclic and the alkyl, aryl and hetaryl groups can be substituted, for example, by alkyl, alkenyl, alkyne, alkylene, aryl, heterocyclyl, hydroxy, carboxy, halogen, alkoxy, aryloxy, heterocyclyloxy, alkylthio, arylthio, heterocyclylthio, alkylseleno, arylseleno, heterocyclylseleno, acyl, acyloxy, acylamino, cyano, nitro, amino, thio or mercapto groups,
wherein a heterocyclyl represents a saturated, unsaturated or aromatic heterocyclic radical and an acyl represents the radical of an aliphatic, olefinic or aromatic carboxylic, carbamic, carbonic, sulphonic, amidosulphonic, phosphoric, phosphonic, phosphorous, phosphinic or sulphinic acid.
Preferably the alkyl groups can be substituted, for example, by alkyl, alkylene, hydroxy, alkoxy or acyloxy groups and most preferably by hydroxy or alkoxy groups. Preferred substituents for aryl and hetarylgroups are halogen, in particular Cl and F, alkyl, fluorinated alkyl, cyano, acyl, acylamino or carboxy groups.
Suitable cyan couplers are:
Synthesis of the Phenolic Coupler Intermediate Stage 
A solution of 185 g (0.87 mol) 3,4-dichlorobenzoylchloride 2 in 50 ml N-methylpyrrolidone was added dropwise while stirring to 165 g (0.87 mol) 2-amino-4-chloro-5-nitrophenol 1 in 500 ml N-methylpyrrolidone. The mixture was subsequently stirred for 1 hour at ambient temperature and then for 2 hours at 60 to 65xc2x0 C. After cooling 500 ml water were slowly added and suction filtered. The mixture was then stirred twice with water, then twice with methanol and suction filtered.
Yield 310 g (98%) 3.
A mixture of 310 g (0.86 mol) 3, 171 g iron powder, 2.2 l ethanol and 700 ml N-methylpyrrolidone were heated to 65xc2x0 C. while stirring. The heating bath was removed and 750 ml concentrated hydrochloric acid were added dropwise within 2 hours. The mixture was then refluxed for 1 hour. After cooling, 1 l water was added and suction filtered, the mixture washed with 2 N hydrochloric acid then with water until the discharge water was colourless. The residue was stirred with 1:5 l water, neutralised by the addition of sodium acetate and suction filtered. The mixture was stirred again twice with 1.5 l methanol and suction filtered.
Yield 270 g (95%) 4.
Synthesis of the Ballast Residue 
320 g (3.6 mol) 45% sodium hydroxide solution were added dropwise while stirring within 1 hour to a mixture of 520 g (3.6 mol) 4-chlorothiophenol 5 and 652 g (3.6 mol) 2-bromoethylbutyrate 6 in 1 l ethanol. The reaction was strongly exothermic, the temperature was kept at 75 to 80xc2x0 C. by cooling, and the mixture was then refluxed for 1 hour. A further 400 g (4.5 mol) sodium hydroxide solution were slowly added (weakly exothermic). After a further 2 hours of refluxing the mixture was cooled and 1 l water was added to it. The mixture was then extracted twice with 250 ml toluene, and the purified organic phases were dried and evaporated on the rotary evaporator. The viscous oil 7 (830 g, still containing toluene) was further reacted without purification.
760 ml hydrogen peroxide (35%) were added dropwise to a solution of 830 g (3.6 mol) of compound 7 and 10 ml sodium tungstate solution (20%) in glacial acetic acid: the first 300 ml initially with cooling at 35 to 40xc2x0 C., the remaining 360 ml at 90 to 95xc2x0 C. after removal of the cooling. Once the addition was complete the mixture was subsequently stirred at this temperature for 1 hour. Excess peroxide was destroyed by the addition of sodium sulphite. 2 l ethyl acetate and 2 l water were added to the reaction mixture, the organic phase was separated off and the aqueous phase extracted twice with 700 ml ethyl acetate respectively. The combined organic phases were washed twice with 700 ml water respectively, dried and evaporated under vacuum. The residue was dissolved hot in 300 ml ethyl acetate, cooled and combined with 1 l hexane at the start of crystallisation. The mixture was then suction filtered cold and rewashed with a little hexane. 835 g (88%) of compound 8 were obtained.
131 g (0.5 mol) 8 and 111 g (0.55 mol) dodecylmercaptan 9 were introduced into 300 ml 2-propanol while stirring with 90 g (1 mol) sodium hydroxide solution (45%). After addition of 2.5 g tetrabutylammonium bromide and 2.5 g potassium iodide, the mixture was refluxed for 11 hours. After cooling 350 ml water were added, and the pH was adjusted to 1 to 2 with about 60 ml concentrated hydrochloric acid. The mixture was then extracted twice with 100 ml ethyl acetate, the combined organic phases were washed three times with 150 ml water respectively, dried and evaporated. The residue was stirred with 500 ml hexane and suction filtered at 0 to 5xc2x0 C. After recrystallisation 177 g 10 (82%, mp.: 82xc2x0 C.) were obtained from 500 ml hexane/ethyl acetate (10:1).
128 g (0.3 mol) 10 and 1 ml dimethylformamide were heated in 300 ml toluene to 65xc2x0 C. 75 ml (1 mol) thionylchloride were added dropwise at this temperature within 1 hour. After a further 5 hours the mixture was evaporated under vacuum. The highly viscous oil (11, 134 g) was used without further purification.
Synthesis of the Coupler 1-10
100 g raw product 11 (about 0.2 mol) in 100 ml N-methylpyrrolidone were added dropwise at 5 to 10xc2x0 C. to 66 g (0.2 mol) 4 in 200 ml N-methylpyrrolidone. The mixture was initially stirred for 2 hours at ambient temperature then for 2 hours at 60xc2x0 C. The reaction mixture was filtered hot, 500 ml acetonitrile added to the filtrate, the mixture cooled to 0xc2x0 C., suction filtered and then washed with 50 ml acetonitrile. The product was combined with 500 ml methanol and 1 l water, stirred, suction filtered, then rewashed with 300 ml water and dried.
Yield: 120 g (81%) I-10.
The red-sensitive layer may contain silver chloride, silver chloride bromide, silver chloride iodide or silver chloride bromide iodide crystals. It is particularly preferably a silver chloride bromide emulsion with a chloride content of at least 95 mol % and particularly preferably of at least 97 mol %.
Preferred compounds of formula (II) are listed hereinafter:
In a preferred embodiment the red-sensitive layer additionally contains a compound of the formula 
wherein
R14 represents a substituent and
n represents a number 1, 2 or 3.
The compound of formula (III) is preferably contained in the red-sensitive layer in an amount of 100 to 5,000 mg per kg Ag and in particular in an amount of 500 to 3,000 mg per kg Ag.
Particularly suitable stabilisers of formula (III) are those in which R14 has the meaning 
and
R15 and R16 independently of one another represent H, Cl, C1 to C4 alkyl, phenyl or chlorophenyl.
A compound of formula 
is particularly preferred.
In a particularly preferred embodiment the red-sensitive layer contains a red sensitiser of formula 
wherein
R17 to R24 represent H, alkyl, alkoxy, halogen, aryl, CN, 2- or 3-thienyl, N-pyrrolyl, N-indolyl, benzthienyl, CF3, 2- or 3-furanyl or
R18 and R19 or R19 and R20 or R21 and R22 or R22 and R23 represent the remaining members of a carbocyclic ring system.
X1 and X2 represent O, S, Se or Nxe2x80x94R27,
R25 and R26 represent optionally substituted alkyl or R23 together with L1 or R26 together with L5 represent the remaining members of a 5- to 7-membered saturated or unsaturated ring,
L1 to L5 represent optionally substituted methine groups or L2, L3 and L4 together represent the members of a 5- to 7-membered ring,
m represents 0 or 1
R27 represents C1 to C4 alkyl and
M represents a counterion optionally necessary for charge compensation,
wherein X1 and X2 independently of one another represent S or Se if m is 0.
The compounds of formula (IV) are preferably contained in the red-sensitive layer in an amount of 5 to 250 xcexcmol per mol silver halide and particularly preferably in an amount of 50 to 200 xcexcmol per mol silver halide.
Particularly preferred sensitisers of formula (IV) are given hereinafter: 
In a particularly advantageous embodiment of the invention the sensitisers of formula (IV) are those of formula 
wherein
S1, S2 independently of one another represent optionally substituted alkyl, sulphoalkyl, carboxyalkyl, xe2x80x94(CH2)xe2x80x94SO2xe2x80x94NYxe2x80x94SO2-alkyl, xe2x80x94(CH2)xe2x80x94SO2xe2x80x94NYxe2x80x94CO-alkyl, xe2x80x94(CH2)xe2x80x94COxe2x80x94NYxe2x80x94SO2-alkyl, xe2x80x94(CH2)xe2x80x94COxe2x80x94NYxe2x80x94CO-alkyl,
Y represents a negative charge or a hydrogen atom,
R28, R29, R30, R31, R32, R33 independently of one another represent H, alkyl, alkoxy, halogen, aryl, CN, 2- or 3-thienyl, N-pyrrolyl, N-indolyl, benzthienyl, CF3, 2- or 3-furanyl or
R28 and R29 or R29 and R30 or R31 and R32 or R32 and R33 represent the remaining members of a benzo or naphtho ring,
R34, R35 independently of one another represent H, alkyl, aryl or hetaryl and
M represents a counterion optionally required for charge compensation.
Particularly favourable properties are achieved if the red-sensitive layer, in addition to sensitisers of formula (IV-A), additionally contains those of formula 
wherein
S3, S4 independently of one another have the same meaning as S1, S2,
R42, R43 independently of one another have the same meaning as R34, R35,
R36, R37, R38, R39, R40 and R41 have the same meaning as R28 to R33 and
M represents a counterion optionally required for charge compensation.
Suitable sensitisers of formulae (IV-A) and (IV-B) are given hereinafter: 
The sensitisers of formula (IV-A) are preferably used in an amount of 10 to 250 xcexcmol, the sensitisers of formula (IV-B) in an amount of 5 to 200 xcexcmol per mol silver halide.
In a particularly preferred embodiment the red-sensitive layer, in addition to the red-sensitisers of formulae (IV) and/or (IV-A) and/or (IV-B), contains a further red-sensitiser of formula 
wherein
R44 to R51 represent H, alkyl alkoxy, halogen, aryl, CN, 2- or 3-thienyl, N-pyrrolyl, N-indolyl, benzthienyl, CF3, 2- or 3-furanyl or R45 and R46 or R46 and R47 or R48 and R49 or R49 and R50 represent the remaining members of a carbocyclic ring system,
X3 represents O, S, Se or Nxe2x80x94R54,
X4 represents 0 or Nxe2x80x94R55 
R52 and R53 represent optionally substituted alkyl or R52 together with L6 or R53 together with L8 represent the remaining members of a 5- to 7-membered saturated or unsaturated ring,
L6 to L8 represent optionally substituted methine groups,
R54 and R55 represent C1 to C4 alkyl and
M represents a counterion optionally necessary for charge compensation.
Particularly suitable sensitisers of formula (V) are given hereinafter 
The invention also relates to a method for producing a positive image to be viewed by reflection of a colour negative, characterised in that a colour photographic material according to the invention is used.
In the method according to the invention, exposure is preferably carried out with a scanning or analogue copier.
The compounds of formulae 1 to 4 are added, in particular, after chemical digestion, compound (II) optionally also during chemical digestion.
In a preferred embodiment the silver halide crystals of the red-sensitive layer are doped with iridium.
The iridium may be incorporated into the crystals in any known manner. It is preferably added as a complex salt in dissolved form at any time during emulsion production, in particular before the end of precipitation.
In a preferred embodiment iridium (III)- and/or iridium (IV)-complexes are used, complexes with chloroligands being preferred. Hexachloro iridium (III)- and hexachloro iridium (IV)-complexes are preferred. The counterions to the iridium complex ions optionally required for charge compensation do not influence the effect according to the invention and may be selected freely.
Further preferred embodiments of the invention may be found in the sub-claims.
Examples of colour photographic copying materials are colour photographic paper, colour reversal photographic paper, semi-transparent display material and colour photographic materials with workable bases, for example made of PVC. An overview may be found in Research Disclosure 37038 (1995), Research Disclosure 38957 (1996) and Research Disclosure 40145 (1997).
The photographic copier materials consist of a substrate to which at least one light-sensitive silver halide emulsion layer is applied. In particular thin films and foils are suitable as substrates. An overview of substrate materials and auxiliary layers applied to the front and back thereof is given in Research Disclosure 37254, part 1 (1995), page 285 and in Research Disclosure 38957, part XV (1996), page 627.
The colour photographic copier materials conventionally contain at least one respective red-sensitive, green-sensitive and blue-sensitive silver halide emulsion layer and optionally intermediate layers and protective layers.
These layers may be arranged differently, depending on the type of photographic copying material. This is shown for the most important products:
Colour photographic paper and colour photographic display material in the sequence on the substrate given below conventionally have a respective blue-sensitive, yellow-coupling silver halide emulsion layer, a green-sensitive, magenta-coupling silver halide emulsion layer and a red-sensitive, cyan-coupling silver halide emulsion layer. A yellow filter layer is not necessary.
Deviations from the number and arrangement of the light-sensitive layers may be made to achieve specific results. For example colour papers may also contain intermediate layers sensitised in a different way, via which the gradation may be influenced.
Binders, silver halide particles and colour couplers are essential components of the photographic emulsion layers.
Details on suitable binders may be found in Research Disclosure 37254, part 2 (1995), page 286 and in Research Disclosure 38957, part II.A (1996), page 598.
Details on suitable silver halide emulsions, their production, digestion, stabilisation and spectral sensitisation, including suitable spectral sensitisers, may be found in Research Disclosure 37254, part 3 (1995), page 286, in Research Disclosure 37038, part XV (1995), page 89 and in Research Disclosure 38957, part V.A (1996), page 603.
Pentamethine cyanins with naphthothiazole, naphthoxazole or benzthiazole as basic terminal groups may also be used as red-sensitisers for the red-sensitive layer, which may be substituted by halogen, methyl or methoxy groups and may be 9,11-alkylene-, in particular 9,11-neopentylene-bridged.
The N,Nxe2x80x2-substituents may be C4 to C8 alkyl groups. The methine chain may also carry substituents. Pentamethines with only one methyl group on the cyclohexene ring may also be used. The red-sensitiser may be supersensitised by adding hetrocyclic mercapto compounds and stabilised.
The red-sensitive layer may additionally be spectrally sensitised between 390 and 590 nm, preferably at 500 nm, in order to bring about improved differentiation of the red tones.
The spectral sensitisers may be added to the photographic emulsion in dissolved or dispersed form. Both solution and dispersion may contain additives such as wetting agents or buffers.
The spectral sensitisers or a combination of spectral sensitisers may be added before, during or after preparation of the emulsion.
Photographic copying materials contain either silver chloride bromide emulsions with up to 80 mol % AgBr or silver chloride bromide emulsions with over 95 mol % AgCl.
Details on the colour couplers may be found in Research Disclosure 37254, part 4 (1995), page 288, in Research Disclosure 37038, part II (1995), page 80 and in Research Disclosure 38957, part X.B (1996), page 616. The maximum absorption of the colours formed from the couplers and the colour developer oxidation product is, for copying materials, preferably in the following ranges: yellow coupler 440 to 450 nm, magenta coupler 540 to 560 nm, cyan coupler 625 to 670 nm.
The yellow couplers conventionally used in copying materials in association with a blue-sensitive layer are virtually always two-equivalent couplers of the pivaloylacetanilide and cyclopropylcarbonylacetanilide series.
The magenta couplers conventional in copying materials are virtually always those from the series of anilinopyrazolones, the pyrazolo[5,1-c](1,2,4)triazoles or the pyrazolo[1,5-b](1,2,4)triazoles.
The non-light-sensitive intermediate layers generally arranged between layers of different spectral sensitivity may contain agents to prevent undesired diffusion of developer oxidation products from one light-sensitive layer into another light-sensitive layer with different spectral sensitisation.
Suitable compounds (white couplers, scavengers or EOP catchers) may be found in Research Disclosure 37254, part 7 (1995), page 292, in Research Disclosure 37038, part III (1995), page 84 and in Research Disclosure 38957, part X.D (1996), S. 621 ff.
The photographic material may also contain UV light absorbing compounds, optical brighteners, spacers, filter colours, formalin scavengers, light stabilisers, antioxidants, DMin-colours, softeners (latices), biocides and additives for improving the coupler and colour stability, for reducing the colour haze and for reducing the yellowing, etc. Suitable compounds may be found in Research Disclosure 37254, part 8 (1995), page 292, in Research Disclosure 37038, parts IV, V, VI, VII, X, XI and XIII (1995), page 84 ff and in Research Disclosure 38957, parts VI, VIII, IX and X (1996), page 607 and 601 ff.
The layers of colour photographic materials are conventionally hardened, i.e. the binder used, preferably gelatin, is crosslinked by suitable chemical processes.
Suitable hardener substances may be found in Research Disclosure 37254, part 9 (1995), page 294, in Research Disclosure 37038, part XII (1995), page 86 and in Research Disclosure 38957, page II.B (1996), page 599.
In terms of image-wise exposure, colour photographic materials are processed by different processes according to their character. Details on procedures and chemicals required for them are published in Research Disclosure 37254, page 10 (1995), page 294, in Research Disclosure 37038, parts XVI to XXIII (1995), page 95 ff and in Research Disclosure 38957, parts XVIII, XIX and XX (1996), page 630 ff, together with exemplary materials.